1. Field of the Invention
The present invention relates to an electrical connector, and in particular to an electrical connector which provides suitable impedance for balanced transmission.
2. Description of Related Art
With the development of communication and computer technology, high density electrical connectors with conductive elements in a matrix arrangement are desired to construct a large number of signal transmitting paths between two electronic devices. Such high density electrical connectors are widely used in internal connecting systems of severs, routers and the like devices requiring high speed data processing and communication.
U.S. Pat. No. 6,183,302 issued to Osamu Daikuhara et al. and on Feb. 6, 2001 discloses a high density connector which includes a dielectric housing, a plurality of signal and grounding contacts alternately disposed in the dielectric housing, wherein the first and second signal contacts can provide about 50 xcexa9 impedance. However, in this way, the impedance of each signal contact cannot be accurately controlled in a suitable range. Specially, in differential pair technique, the steady impedance is the key to balanced transmission. By the way, the differential pair of technique means that a signal is transmitted via two paths, wherein each path has the same length as the other path. Furthermore, even we can improve impedance function of the signal contacts via modifying shape or size of the signal contacts, but these methods are wasteful, which cannot be easily used in any condition, specially for some connectors having definite standard.
It is thus desirable to provide an electrical connector which can resolve above problem in prior art.
Accordingly, an object of the present invention is to provide an electrical connector which can satisfy the impedance needs of application.
In order to achieve the object set forth, an electrical connector in accordance with the present invention comprises an upper housing, a bottom housing and a terminal module. The upper housing and the bottom housing together define a space and a mating port positioned near the space. The terminal module has a base, a tongue extending in the mating port from the base, and a plurality of signal and grounding terminals therein. The signal terminals are disposed opposite sides of the tongue in pairs. A square hole is formed in the tongue and parallel to the signal terminals.
Furt hermore, the tongue defines a plurality of through grooves and grooves arranged alternately to each other. The terminal module may comprise a circuit board for engaging with the first grounding terminals and signal terminals. The grounding terminals consist of first grounding terminals for engaging with a mating connector and second grounding terminals for shielding the signal terminal.